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New variety of salt-tolerant wheat could help address food shortages

A new type of wheat bred with a gene that removes sodium from water can outgrow conventional strains by up to 25% in salty…

Salt-resistant crops will be a boon for farmers whose properties are increasingly affected by salinity. EPA/Larry W. Smith

A new type of wheat bred with a gene that removes sodium from water can outgrow conventional strains by up to 25% in salty soils, Australian scientists have found.

The breakthrough by a team from CSIRO and the University of Adelaide was achieved with non-genetically modified (GM) crop breeding techniques, and could be an important asset for farmers worldwide as they cope with the effect of climate change on soil salinity.

Scientists from CSIRO Plant Industry in Canberra identified the gene, from an ancient strain of wheat, more than 15 years ago, and researchers at the University of Adelaide’s Waite Research Institute led the effort to understand how it delivers salt tolerance to the plants.

The results are published today in the journal Nature Biotechnology. The paper’s senior author, Matthew Gilliham from the Waite Research Institute, said that the achievement was significant as “salinity already affects over 20% of the world’s agricultural soils, and salinity poses an increasing threat to food production due to climate change”.

Dr Gilliham added: “Salinity is a particular issue in the prime wheat growing areas of Australia, the world’s second-largest wheat exporter after the United States. With global population estimated to reach nine billion by 2050, and the demand for food expected to rise by 100% in this time, salt-tolerant crops will be an important tool to ensure future food security.”

Domestication and breeding has narrowed the gene pool of modern wheat, leaving it susceptible to environmental stress. Durum wheat, used for making pasta and couscous, is particularly susceptible to soil salinity. But the researchers discovered that the new salt-tolerant gene in an ancestral cousin of modern-day wheat, Triticum monococcum, could help.

“Salty soils are a major problem because if sodium starts to build up in the leaves it will affect important processes such as photosynthesis, which is critical to the plant’s success,” Dr Gilliham said.

“The salt-tolerant gene works by excluding sodium from the leaves. It produces a protein that removes the sodium from the cells lining the xylem, which are the pipes plants use to move water from their roots to their leaves,” he said.

CSIRO’s Richard James, who led the field trials, said that whereas most studies only looked at performance under controlled conditions in a laboratory or greenhouse, this study confirmed that the salt-tolerant gene worked in commercial conditions.

The researchers conducted field trials at a variety of sites across Australia, including a commercial farm in northern New South Wales.

The salt-tolerant wheat would now be used by the Australian Durum Wheat Improvement Program (ADWIP) to assess its impact by incorporating this into recently developed varieties as a breeding line, he said.

Rana Munns, from CSIRO, said new varieties of salt-tolerant durum wheat could be a commercial reality in the near future. “Although we’ve used molecular techniques to characterise and understand the salt-tolerant gene, the gene was introduced into the durum wheat through non-GM breeding processes. This means we’ve produced a novel durum wheat that is not classified as transgenic, or GM, and can therefore be planted without restriction,” Dr Munns said.

The team is now hoping to develop the salt-resistant strain for bread wheat.